In certain electrophotographic applications such as color xerography, a charge retentive surface moving in a process direction is electrostatically charged and exposed to a light pattern of an original image to be reproduced to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on that surface form an electrostatic charge pattern (an electrostatic latent image) conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder or powder suspension referred to as "toner". Toner is held on the image areas by the electrostatic charge on the surface. Subsequently, a second image can be formed over the first image, by providing a re-charge station, a second exposure station and a second development arrangement. Subsequent extension of this basic process can be understood to form the basis for producing multiple color images. Conveniently, an LED bar, an array of light emitting diodes arranged in a linear array and extending across the charge retentive surface, transverse to the process direction may be used as an exposure device. However, such an arrangement has no intrinsic built-in means for compensating for uncontrolled travel or mechanical drift of the charge retentive surface (commonly a belt) in the cross process direction. This becomes especially important for color images where misregistration of the different colors by as little as a fraction of a pixel width can seriously detract from image quality.